Applying of SP, DC-Resistivity, DC-TDIP and TDEM soundings in high saline coastal aquifer.

Four surface geophysical techniques were utilized to study the geological and hydrogeological settings of highly saline a coastal aquifer system to the north-east of River Nile Delta, Egypt. These techniques include SP, DC-Resistivity, TDIP and TDEM methods. The first target was to determine the geological stratification as a differentiation among clay, clayey, sand and sandy layers of high saline water. These techniques reflect that there is a complicated lateral and vertical difference in sediments along study area. The surface layers with depth down to ~120 m have low to medium content of clay that change with depth. Then, the second target was the differentiation laterally and vertically for salinity with depth down to ~250m as an interesting hydrogeological setting. These techniques reported that the sediments consist of thin and thick clay and silts, clayey sand, and sandy clay strata. Investigation depth was up to ~210m due to high salinity and clay content effect. At shallow depths, soil texture (down to ~100m and sometimes down to ~160m) consists of clay and silt with sand intercalation. The TEM data indicate a zone of less saline water and low clay content starting from ~40 to ~100m. There may be an evidence for a significant high to medium clay content after these depths down to ~250m. All four methods were calibrated with each other. Accordingly, good matching between the inversion model of TEMSs and composite logs of new drilled well was found, especially in lithological layers identifications. Also, this calibration confirmed that the area was complicated regarding the geological and hydrogeological conditions and the TDIP and TEM are the best methods in studying the environmental, geological and hydrogeological settings as primary important engineering implications for studying coastal highly saline aquifers.

A monoclonal antibody-based enzyme immunoassay for detecting parasite antigenaemia and antigenuria in Schistosomiasis mansoni.

Both specific polycolonal antibody and monoclonal antibody against the microsomal antigen of adult S. mansoni were used to detect antigenaemia and antigenuria by antigen-capture sandwich ELISA in the sera and urine of patients infected with S. mansoni and other parasites. Antigenaemia was detected in 22 sera out of 100 of patients infected with S. mansoni but no antigenuria was detected. None of the sera of S. mansoni free patients were positive for microsomal antigen. More standardization of the technique and more refining of the reagents used is required to improve the sensitivity of the test.

Evaluation of the response of human humoral antibodies to Salmonella typhi lipopolysaccharide in an area of endemic typhoid fever.

Because of the limited value of Widal's test in the diagnosis of typhoid fever in areas of endemicity, individual serum levels of IgM, IgA, IgG, and IgG subclass antibodies to Salmonella typhi lipopolysaccharide were evaluated in samples collected in Egypt. The study involved 106 febrile patients, including 40 patients for whom cultures were positive for S. typhi and 66 patients for whom diseases other than typhoid were diagnosed. Multivariate regression modeling revealed that detection of the combination of IgA, IgG, and IgG2 correlated best, although not perfectly (adjusted r(2) = 68), with a positive culture; the sensitivity and specificity of testing for IgA, IgG, and IgG2 (i.e., all three tests positive vs. all three tests negative) were 91.7% and 98.1%, respectively. These results suggested that testing for IgA, IgG, and IgG2 in combination is of diagnostic value for S. typhi infection.

Applicability of ELISA on buffer-eluates of capillary blood spotted on filter papers for the diagnosis and clinical staging of human schistosomiasis.

The relative concentrations of IgM and IgG antibodies (Ab) to Schistosoma mansoni soluble egg antigen (SEA) were evaluated in paired samples of venous blood sera and buffer-eluates of capillary blood drops dried on filter papers. The samples were obtained from school children at early and chronic stages of schistosomiasis diagnosed on the basis of history, clinical symptomatology and parasitological criteria. Enzyme-linked immunosorbent assay (ELISA), simultaneously performed, revealed paired samples to display comparable Ab levels in all cases. Samples from children with early schistosomiasis had specific IgM:IgG ratios greater than 1 [optical densities (O.D.) in sera and blood eluates of 0.77 +/- 0.32 and 0.68 +/- 0.30, respectively for IgM and 0.52 +/- 0.25 and 0.50 +/- 0.25 for IgG]. This ratio, however, was less than 1 in samples from chronically infected children (O.D. of 0.20 +/- 0.11 and 0.20 +/- 0.11 for IgM and 0.69 +/- 0.33 and 0.73 +/- 0.32 for IgG). The specific advantages of this simplified technique are the use of anti-SEA Abs in fingerstick blood eluates, rather than sera of venous blood to serologically diagnose schistosomiasis and to differentiate early from chronic infections particularly when used for mass screening, such as epidemiologic surveys.

Serodifferentiation of human fascioliasis from schistosomiasis.

A dot enzyme-linked immunosorbent assay (dot-ELISA) was developed using excretory-secretory (ES) antigens of Fasciola gigantica adult worms and freeze-thaw antigen (AFT) of adult Schistosoma mansoni worms. Specific IgG and IgM antibodies were simultaneously investigated in sera from 17 febrile eosinophilic hospitalized patients and 20 healthy controls. Dot-ELISA was shown useful and could differentiate fascioliasis from schistosomiasis prior to parasite egg detection in patient's stool. This assay is field and laboratory applicable.

Immunological response to diphtheria/tetanus vaccine in Schistosomiasis mansoni patients.

The cellular and humoral immune responses of patients with S. mansoni infection were evaluated before and one month after each of two intramuscular doses of diphtheria/tetanus toxoid vaccine. Patients were divided into "responder" and "non-responder" groups based on anti-tetanus toxoid (anti-TT) IgG levels after vaccination. The specific anti-TT IgG1 response of the responder group was predominantly in the IgG, subclass. The lymphoproliferative response to PHA was also significantly higher in the responder group; this elevation was detectable before and after each vaccination. The responses to PWM and SPL were comparable in the two groups before vaccination, although the responder group had a higher response to SPL after vaccination. IgG antibodies for schistosome adult worm and egg antigens were significantly lower in the responder group prior to vaccination but not thereafter. Anti-diphtheria IgG antibodies were comparable in the two groups after vaccination at all times. Clinically, the non-responder patients had a higher incidence of splenomegaly (84.6% vs 44.8%) and were significantly older than the responder patients (mean 34.1 yrs vs 18.7 yrs). The cause for the reduced anti-tetanus IgG response in schistosomiasis patients is believed to be multifactorial. T cell or antigen presenting cell dysfunction, high levels of IgG antibodies specific for schistosome antigens, splenomegaly and age are factors that might lead to reduced anti-TT IgG response.

Diagnosis of human schistosomiasis by detection of circulating cathodic antigen with a monoclonal antibody.

Monoclonal antibody (MAb) 5H11 reacted with repeating epitopes on Schistosoma mansoni circulating cathodic antigen (CCA) and detected CCA in sera of Egyptian S. mansoni-infected patients. MAb 5H11 was both capture and biotinylated detection antibody in a sandwich ELISA of trichloroacetic acid-pretreated serum samples. Sera of patients with 7-500 eggs/g of stool were positive by MAb 5H11-CCA sandwich ELISA. Stool egg counts and CCA serum levels correlated (r = .52), and CCA levels decreased by 4 weeks after praziquantel treatment in patients with pretreatment egg counts of greater than or equal to 50/g of stool (P less than .05). Sera of Schistosoma haematobium-infected patients, uninfected individuals, and most patients with other helminths were negative in this assay. The MAb 5H11-CCA sandwich ELISA appears sensitive and specific for immunodetection of active schistosomiasis mansoni and useful for monitoring its chemotherapy.

Vaccine induced immunity to Schistosoma mansoni: spleen cell proliferative responses before and after challenge in BALB/c mice given irradiated or normal schistosomula.

Spleen cell proliferative responses in BALB/c mice were assessed at varying intervals after vaccination or primary infection and subsequent cercarial challenge. Mice were vaccinated with 500 50-Krad-irradiated Schistosoma mansoni schistosomula or infected with 20 normal schistosomula. Prior to challenge, splenic responses in the two test groups to phytohemagglutinin (PHA) declined progressively while schistosomula (SMA)-driven responses increased. After challenge, PHA responses increased in both groups on day 3 then declined to significantly lower levels compared to normal controls. On day 3 after challenge, SMA responses in vaccinated mice were vigorous, and greater than twice the responses in infected mice. Thereafter, responses in vaccinated mice declined while responses in infected mice increased on days 7 through 25 but dropped markedly by day 39. For the infected group, in vitro depletion of plastic adherent cells or Lyt 2.2+ lymphocytes resulted in augmented SMA responses 3 days post-challenge by greater than 400% and greater than 100%, respectively. Depletion of either cell population in the vaccinated group had no significant effect. Protection assessed by total worm burdens showed a reduction of 62% in vaccinated mice and 43% reduction in infected mice. The post-challenge results indicate that these two models of anti-schistosomula immunity differed in the dynamics of their splenocyte antigen-specific proliferative responses. These findings may contribute to an understanding of the mechanisms by which resistance to S. mansoni is induced.

Schistosoma mansoni: detection of circulating antigens in murine schistosomiasis by antigen-capture sandwich ELISA using a monoclonal antibody.

A monoclonal antibody (MAb) 5H11/B1 that reacts with a repeating epitope on an excretory-secretory (E + S) antigen of adult worms of Schistosoma mansoni was used in the detection of circulating antigen (CA) in sera from S. mansoni-infected mice using an antigen-capture sandwich ELISA. Trichloroacetic acid (TCA) pretreatment of sera from mice infected for 8 or 16 weeks precipitated immune complexes and/or dissociated CA and allowed its detection. Sera obtained 8 weeks after infection contained high levels of CA. Upon treatment with praziquantel (100 mg/kg body wt), this level was significantly less within 1 week. A strong correlation was found between the worm count determined by perfusion and the level of antigenemia detected by the 5H11/B1 assay in light and heavy infection (r = 0.80). Based on the results of both TCA pretreatment and sodium periodate treatment, the 5H11/B1 sandwich ELISA assay detects a repeating carbohydrate epitope on an E + S antigen. This system appears to be a sensitive assay for the detection of schistosomal antigenemia in murine schistosomiasis. Studies on the detection of antigenemia in human schistosomiasis using this assay are in progress.

Total leucocytic count, eosinophilia and cellular immune response in acute and chronic schistosomiasis.

Among school children in a rural area the serological diagnosis (ELISA) was more accurate than the parasitological tests. The mean total leucocytic and eosinophilic counts, and the blastogenic response to S. mansoni egg antigen were significantly higher in early than in chronic schistosomal cases. Blastogenic response to mitogens and S. mansoni adults preparation was insignificantly different.

Dot-enzyme-linked immunosorbent assay (dot-ELISA) for the diagnosis of schistosomiasis.

We describe a dot enzyme-linked immunosorbent assay (dot-ELISA) as a field applicable tool for the rapid diagnosis of schistosomiasis. This antibody capture assay is performed using 50 ng protein of crude Schistosoma mansoni egg antigen (SEA) in 1 microliter volumes per dot. Sera (1 microliter/dot) at 1:40 dilution were optimal. Dot-ELISA results were completely comparable to micro-ELISA.

Dot-enzyme-linked immunosorbent assay (dot-ELISA) for the rapid diagnosis of human fascioliasis.

A dot-enzyme-linked immunosorbent assay (dot-ELISA) was developed as a fast and field applicable antibody detection tool for the diagnosis of human fascioliasis. The assay is performed using partially purified antigens from a species of Fasciola at 180 ng protein/dot (2 microliters) and serum samples at 1:20 dilution (1 microliter). Dot-ELISA results completely agreed with those of micro-ELISA. Antigen-coated nitrocellulose sheets stored for 3 mo at -20 C showed results identical to fresh sheets. Sera from patients with fascioliasis (n = 30) and other parasitic or viral infections (n = 120) were compared with sera from healthy controls (n = 14). Ninety samples can be tested within 90 min. The sensitivity, specificity, and speed of the assay may justify its use in laboratory and field studies.

Transmission of lymphocyte responsiveness to schistosomal antigens by breast feeding.

Fifty normal infants were evaluated for the influence of their feeding pattern on the mother-to-child transmission of lymphocyte responsiveness to Schistosoma mansoni antigens. Positive delayed-type hypersensitivity reactions (DTH) were observed in 56% of infants who were breast-fed by infected mothers. Two out of 20 formula-fed infants born to infected mothers had positive DTH. A positive DTH was detected in only one infant out of 15 breast-fed by schistosomiasis-free mothers. These results suggest that cellular hypersensitivity to S. mansoni antigen can - at least in part - be transmitted in the colostrum/milk of infected mothers to their infants.

Modulatory effects of Schistosoma mansoni infection on bone marrow granulopoietic and erythropoietic activity in mice.

Bone marrow (BM) cells from BALB/c mice infected with mixed-sex Schistosoma mansoni cercariae were assessed for their capacity to form in vitro colony forming units of erythroid (CFU-e) and granulocyte/macrophage (CFU-c) cells. At four weeks after infection, substantial BM commitment to granulopoiesis was noted by an increase in CFU-c, with no changes in CFU-e. Elevated marrow granulopoietic activity, although to a lesser extent, was also observed five weeks after either male or female cercarial infection. Preferential differentiation of precursor cells into eosinophilic and/or neutrophilic lineages was observed at weeks four and six post bisexual cercarial infection. After eight weeks of mixed infection, there was a marked suppression of CFU-e formation as compared with uninfected or single sex cercariae-infected mice. These results demonstrate that S. mansoni infection appears to influence either the differentiation capacity or the levels of BM cells at the progenitor cell level, and that maturation of worms and/or oviposition may contribute to changes in the CFU-e and CFU-c cell differentiation.

Granulocyte precursor cell studies in Schistosoma mansoni patients with eosinophilia.

Eosinophilia is a common clinical presentation in patients with helminthic infections. A study was designed to determine the mechanism(s) for selective or preferential differentiation of precursor cells into mature eosinophils (eos). Thus, experiments were performed to delineate the frequency of colony forming units of eos (CFU-eos) in the peripheral blood of Egyptian patients with active Schistosoma mansoni infection with eosinophilia and normal healthy individuals. The number of CFU-eos among the nonadherent mononuclear cell population was assessed in a double layer soft agar culture with autologous unfractionated mononuclear cells serving as a source of colony stimulating factor(s). Following 14 days of incubation, discrete colonies were distinguished morphologically as eosinophilic, neutrophilic, or mixed. Results indicated a two-fold increase in the total number of colonies per 10(6) cultured nonadherent cells in patients with S. mansoni infection when compared to the number of colonies obtained with adult normal volunteers (57 +/- 10 vs. 24 +/- 4; P less than 0.025). However, the frequency of CFU-eos and CFU-neut was similar in patients and normal individuals (66 +/- 3 vs. 59 +/- 8 percent CFU-eos; 30 +/- 4 vs. 35 +/- 6 percent CFU-neut). These data suggest that: eosinophils may differentiate from progenitor cells at other anatomical sites; there may be an increase in the half life of mature eosinophils in patients; there is no strict correlation between the frequency of progenitor cells and the number of differentiating mature cells of this lineage at least as measured by this in vitro assay; and the in vitro assay may not quantitatively reflect the in vivo differentiating capacity of progenitor cells.

Suppression of mitogen-induced lymphocyte transformation by plasma from patients with hepatosplenic Schistosomiasis mansoni: role of immune complexes.

Plasma from chronic or advanced hepatosplenic schistosomiasis (mansoni) patients (PCS) suppressed mitogen-induced responses of normal human peripheral blood mononuclear cells. 1 x 10(5) Ficoll-Hypaque isolated lymphocytes were cultured in 100 microliter RPMI 1640 media with 100 microliter plasma preparation and stimulated with phytohemagglutinin P (PHA), concanavalin A (Con A), pokeweed mitogen (PWM) and Staphylococcus aureus phage lysate (SPL). Compared to normal human plasma, dose-response experiments with 10-50% PCS uniformly inhibited the 72-h PHA, Con A and PWM responses with maximal suppression at 50% plasma concentration. At this concentration, the range of suppression was 42-60%. The inhibitory activity was unaffected by 56 degrees C, 30 min pretreatment of PCS. However, pre-culture of cells with PHA for 24 h prior to addition of 50% PCS abrogated the suppressor activity. Furthermore, 6-day cultures with PWM and SPL were not suppressed by 50% PCS. Plasma suppressor activity was nearly eliminated by pre-treatment of PCS with 4% (w/v) polyethylene glycol (PEG) in all cases. In the putative immune complexes in the PEG precipitates, Clq, C3, C4, IgG, IgM and IgA were identified in nearly all PCS samples. Schistosomal antigen was found in only two of 23 PCS samples tested and significant anti-schistosomal IgG antibodies were found in all PEG precipitates. The data suggest immune complexes (non-specific and specific) act to suppress 72-h mitogenic responses.

Cell-mediated immune assay in children with Schistosoma haematobium infection and the effect of niridazole therapy.

Forty-five children with Schistosoma haematobium infections were studied utilizing a whole-blood culture technique to assay lymphocyte blast transformation responses. The mitogenic lectins, phytohaemagglutinin (PHA) and pokeweek mitogen (PWM), and heterologous schistosomal antigens from adult worms and eggs were used. Responsiveness to PHA was intact but PWM responses were significantly impaired. Varying responses to schistosomal adult worm antigens were evident. Responses to soluble egg antigens were consistently low. No correlation of lymphocyte transformation responses was evident with egg excretion rates or clinical data. Treatment, primarily with niridazole, resulted in augmented cellular immune responses to PHA, PWM and adult worm antigens and two and eight weeks post-therapy. Anti-egg antigen responses did not significantly change. It was evident that niridazole did not induce cellular immunodepression. The role of schistosome-specific immune modulation is discussed.